Australian scientist: 'dessert stomach' is an evolutionary survival method
The universal experience of finding room in your bloated stomach for a slice of something sweet has been a scientific mystery... until now.
Who isn’t familiar with dessert stomach? It’s a universal experience: you’re full ¬– you can’t eat another morsel. Then someone offers dessert and, miraculously, you find the room for it. Every damn time. This is a widespread oddity of life; there’s even an internet meme devoted to the topic. However, until very recently we had no scientific explanation for this biological process.
But now, thanks to the work of Russell Keast, a sensory and food scientist at Deakin University, Australia, we can add this phenomenon to the great library of ‘solved cases’ the scientific community has compiled over centuries. In an interview with The Huffington Post Australia, Keast gives his findings on sensory specific satiety, or ‘dessert stomach’ as it’s more widely known:
‘A major part of the reason is a phenomenon known as sensory specific satiety. Basically, this is what we experience when we eat one food to fullness. Our senses tell us we are no longer wanting to eat any more of that specific food. In other words, we are full. Part of the response is actually sensory boredom – the food that excited us with promise of flavour delights is now boring. We are getting satiated, but combine this with the fact that our flavour sensing system is overloaded with the food's flavour helps us stop eating.
"Then you present a dessert, a new flavour experience, a different profile to what we are bored with. It may look and smell good and (from experience) we know sweet is appealing. No more boredom with the food and the anticipation creates appetite – hence the dessert stomach.’
According to Keast, our bodies crave the sweet, calorific goodness of dessert so strongly that they override the fullness signals being sent from our stomachs. Keast goes on to explain his methodology:
‘To assess sensory specific satiety (SSS) we provide participants in our sensory tests with 300ml of a strawberry milkshake (or any flavour or any food). We state you must eat the entire portion in two minutes. After the forced intake we then provide the same food to excess, so 700ml of the strawberry milkshake, and ask the participant to have as much or little as they like. We measure the volume consumed and the time taken.
On the participants' next visit we provide the same 300ml of strawberry milkshake to be consumed in two minutes. But then we give them 700ml of chocolate milkshake (another flavour) and ask to consume as much or little as you like. The difference between the volume of chocolate milkshake and strawberry milkshake consumed is a measure of SSS. The new flavour is invariably consumed significantly more than the same flavour.’
Curiously, this isn’t simply a matter of signals from the brain: our stomach actually does become larger to accommodate the new food! Thanks to this evolutionary wiring, sweet things cause our stomachs to relax to allow us to eat more ¬– like the dislocating jaw of a boa constrictor when it lands a big kill. The discomfort comes when our stomach constricts again, giving us that horrible bloated feeling everyone dreads after a big meal.
Predictably, all this comes down to instincts formed to ensure the survival of our species millenia ago:
‘Our stomach and physiology have an ability to adsorb nutrients and energy to excess. Presumably this was a great survival mechanism – in times when food was plentiful you could eat and your body would store what it could.’
Nowadays, and for the majority of the world’s population, food scarcity is no longer an issue, making this crucial evolutionary development something of a hinderance to many of us seeking to undo the damage of an indulgent Christmas in the coming months.